Outboard Motor Steering Handle Throttle Shaft Dynamics
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Solution Overview
Problem
The existing steering handles of outboard motors with throttle and gearshift manipulators face issues where the throttle opening level restriction mechanism restricts necessary throttle manipulations, leading to distortion in the throttle shaft and degradation of steering feeling, especially when the gear position is neutral.
Innovation Solution
A steering handle design that includes a throttle manipulator, a gearshift manipulator, a throttle shaft with a first and second shaft that rotate synchronously, and a conversion mechanism that restricts the second shaft's rotation using an engagement portion dependent on the gearshift manipulator's position, allowing only a predetermined angle of relative rotation to enable necessary throttle manipulations without distorting the throttle shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a throttle opening level restriction mechanism is implemented to prevent excessive engine rotation, then engine safety is improved, but necessary throttle manipulation for warm-up operation is restricted
Solution Approach 1:
The patent applies the dynamics principle by making the throttle shaft configuration adaptable based on gear position. When in gear, the first and second shafts rotate synchronously to restrict throttle opening. When in neutral, the shafts can rotate relatively by a predetermined angle, allowing limited throttle manipulation for warm-up. This dynamic adaptation resolves the contradiction between safety restriction and operational flexibility.
2Reliability
If the throttle shaft is restricted from rotating when gear position is neutral, then engine safety is improved, but distortion is generated in the throttle shaft
Solution Approach 1:
The patent makes the shaft configuration dynamic based on gear position. In neutral position, the shafts are configured to allow relative rotation by a predetermined angle, preventing distortion while still limiting excessive rotation. This dynamic behavior resolves the contradiction between safety restriction and shaft integrity.
Solution Approach 2:
The patent changes the rotational parameter of the throttle shaft based on gear position. When in neutral, the system allows a predetermined angle of relative rotation between shafts, whereas in gear positions it restricts rotation. This parameter change resolves the contradiction by adapting the rotational freedom to the operational context.
3Manufacturing precision
If the throttle shaft is distorted, then meshing accuracy of the gear is degraded, but steering feeling is affected
Solution Approach 1:
The patent applies preliminary anti-action by pre-configuring the shafts to allow relative rotation only within a predetermined angle when in neutral. This prevents excessive rotation that would cause distortion before it occurs, thereby protecting gear meshing accuracy and steering feeling. The restriction is built into the configuration to counteract potential harmful effects in advance.
Data Source
AI summary
A tiller handle includes: a throttle shaft including first shaft and the second shaft; a conversion mechanism configured to convert rotation of the first shaft into a rectilinear motion of the throttle cable; an engagement pin provided in the second shaft; and a restriction member (shift arm) engaged with the engagement pin depending on a position of a selector in synchronization with the selector to restrict rotation of the second shaft in a throttle valve open direction. The first shaft and the second shaft are configured to relatively rotate each other only by a predetermined angle.